Primary Operation in SYnchronous meTastasized InVasivE Breast Cancer

Inclusion Criteria: * Patients age ≥ 18 years * Eastern Cooperative Oncology Group Performance Status is 0 -2 * Untreated synchronous metastasized invasive carcinoma of the breast with the primary tumor in situ (bilateral synchronous metastasized breast cancer patients are eligible) * The primary tumor must be identified and may be any size, however, primary resection with resection free margins must be possible * Invasive adenocarcinoma of the breast on histological examination * The metastatic site must be identified by radiological assessment(Computer Tomography of the chest and the abdomen OR ultrasound and chest x ray for visceral metastases; bone scan AND/OR computer tomography AND/OR magnetic resonance for bone metastases). A biopsy is not necessary. * Written informed consent must be obtained and documented prior to beginning any protocol specific procedures and according to local regulatory requirements * able to comply with the protocol requirements during the treatment and follow-up period. Exclusion Criteria: * Patients in whom a R0 resection (microscopic free margins) is clinically questionable * Inflammatory cancer * Patients with a brain metastasis * Patients who are not eligible for general anesthesia and operations * Patients without metastatic breast cancer (patients with a tumor marker value (CEA, CA15-3) above normal levels without the radiological proven evidence of metastases are not eligible for the study) * Patients with a second untreated malignancy * Any previous malignancy treated with curative intent and the patient has not been disease-free for 5 years - exceptions are: (a)carcinoma in situ of the cervix, (b)squamous carcinoma of the skin, (c)basal cell carcinoma of the skin * Patients with any recurrent cancer disease * Pregnant or lactating women * Patients are not allowed to be part of another local therapy trial